Endocrinology
grrlscientist | May 25, 2010tags: House Finch, Carpodacus mexicanus, birds, mystery bird, bird ID quiz
[Mystery bird] House Finch, Carpodacus mexicanus, photographed in a backyard in Houston, Texas. [I will identify this bird for you in 48 hours]
Image: Joseph Kennedy, 28 March 2010 [larger view].
Nikon D200, Kowa 883 telescope with TSN-PZ camera eyepiece 1/640s f/8.0 at 1000.0mm iso400.
Please name at least one field mark that supports your identification.
This species has an interesting feature that provides insight into its life history -- can you tell me what that feature is and what it reveals about this…
grrlscientist | March 12, 2010tags: evolution, evolutionary biology, gynandromorph, bilateral gynandromorph bird, half-sider, mixed-sex chimaera, sex determination, molecular biology, genetics, developmental biology, endocrinology, birds, chicken, Gallus gallus, ornithology, researchblogging.org,peer-reviewed research, peer-reviewed paper, journal club
Half-sider.
Almost exactly one year ago, hundreds of American birders
were thrilled by sightings and photographs of this remarkable
Northern Cardinal, or Redbird, Cardinalis cardinalis,
photographed in Warrenton, VA.
Image: DW Maiden, 2 March 2009.
I'll never forget…
emjohnson | October 28, 2009As a species we are consumed by love. Ask yourself, how many cultural productions (films, stories, songs, dances, arts) do not have love, the loss of love or the absence of love as their central theme? Would you be satisfied with what was left over? That fact that love has so much power over us is just one reason why evolutionary research is so fascinating.
A well-worn trope of human culture is mens obsession with female infidelity. Othello. Madame Bovary. Desperate Housewives. These are just three Western examples of this concern that are paralleled in nearly every society throughout…
emjohnson | October 26, 2009In a new understanding of the term power grab, researchers have shown that the supporters of a political candidate literally have their power taken from them after they lose an election. In a new study by Steven J. Stanton and colleagues in the open-access journal PLoS ONE, researchers asked 163 Republican and Democratic voters (57 of whom were men) to provide saliva samples both before and after the 2008 election between John McCain and Barack Obama. What the researchers determined was that Republican men showed significant reductions in testosterone after they learned that their candidate…
emjohnson | October 16, 2009Three products that profit on male insecurities (Enzyte, Viagra and Tiger Penis Wine)
Note: the third image is from a campaign to encourage people to stop, not an actual ad.
In my earlier posts I explored why women experience menopause and discussed the Grandmother Hypothesis as a leading explanation. There is accumulating evidence that suggests reproductive senescence in women is an adaptation promoting inclusive fitness. However, there are many claims that menopause also occurs in men. There's even a fancy name for it: andropause.
A quick Google search reveals an onslaught of online "…
emjohnson | October 10, 2009
In the classic film Casablanca, the drama hinges on Ilsa's choice between two men: her kind and supportive husband or her rugged and passionate ex-lover. In a moment of abandon, Ilsa returns to her lover's arms only to later change her mind and choose the more stable life she would have with her long-term partner. But what if something as simple as a pill had caused Ilsa to feel differently and make the opposite choice?
In a new paper in the journal Trends in Ecology and Evolution biologists Alexandra Alvergne and Virpi Lummaa at the University of Sheffield in England raise the possibility…
emjohnson | October 7, 2009Researchers from Simon Fraser University, just a stone's throw from where I sit in Vancouver, have determined that the side effects from this endocrine disruptor can alter children's behavior:
Researchers have just linked prenatal exposure to bisphenol-A - a near-ubiquitous industrial chemical - with subtle, gender-specific alterations in behavior among two year olds. Girls whose mothers had encountered the most BPA early in pregnancy tended to become somewhat more aggressive than normal, boys became more anxious and withdrawn.
Another recent study, by Joe Braun of the University of North…
grrlscientist | February 27, 2008tags: researchblogging.org, endocrine disruptors, environmental pollutants, DDT metabolites, dichlorodiphenyltrichloroethane, birdsong, physiology, behavior
European Starling, Sturnus vulgaris.
Image: Gerd Rossen [larger view].
An elegant but disturbing paper was just published that documents that biologically relevant concentrations of endocrine disrupting pollutants are affecting the quality and quantity of song produced by male songbirds, which in turn, influences female mate choice. According to the research team, not only do these pollutants influence behavior, but they also affect…
grrlscientist | January 10, 2008tags: Ask a Science Blogger, male birth control pill, contraceptive
The human egg at the moment of fertilization.
Image: National Museum of Health and Medicine.
The newest "Ask a Science Blogger" question is; Why is there no birth control pill for men?
I know that many women say that male birth control pills do not exist solely due to sexual politics, namely, why would a pharmaceutical company devote precious research funding to developing a male birth control pill when they can make so much more money from developing drugs such as Viagra? Because I am limited to 500 words or so, I am not…
grrlscientist | August 11, 2007tags: researchblogging.org, osteocalcin, type 2 diabetes, obesity, bones, medicine
Even though bones seem to be metabolically inactive structures, nothing could be further from the truth. In fact, bones are rebuilt constantly through the action of cells known as osteoblasts while old bone is destroyed by other cells known as osteoclasts. Bones also produce red and white blood cells, help maintain blood pH and store calcium. However, exciting new research has shown that bones also act as an endocrine organ. Not only do bones produce a protein hormone, osteocalcin (pictured), that regulates…
grrlscientist | February 9, 2007Researchers at the University of California at Berkeley found that women who sniffed androstadienone (pictured, left), a chemical found in male sweat, experienced elevated levels of cortisol, an important hormone, along with higher sexual arousal, faster heart rate and other effects.
Androstadienone is a metabolite of testosterone that is found in male sweat as well as in saliva and semen. It smells somewhat musky.
This study compared the responses of 48 heterosexual women, with an average age of 21, to baking yeast, but found that yeast did not trigger any effects. They took approximately…